As integrated circuits continue to shrink in size, the shrinking of elements of the integrated circuits can have different impacts on different circuits of the integrated circuit. Examples of elements of integrated circuits which have been reduced in size are transistors and interconnect traces. However, resistors are one element which have not been reduced in size as fast as other elements of integrated circuits. Resistors may often be used in a resistor network, which may have applications in particular circuits such as in a digital-to-analog converter (DAC) circuit. DAC circuits are used extensively in serial-deserializer (Serdes) transceivers, for example, to implement an adaptation algorithm for cancelling the non-ideal effects during data transmission by translating digital inputs into a corresponding analog signal level.
Depending on the specific applications and products, a DAC circuit is designed to meet a number of specifications including resolution, speed, linearity, and power. Different DAC circuit topologies are used in conventional circuits. For example, current steering and resistor ladder DAC circuits are the two common types of DAC circuits. Current steering DAC circuits generally have higher speed when driving capacitive loads, but consume a significant amount of power. In contrast, resistive DAC circuits usually burn less power, but have a larger output impedance which is a drawback for high speed operation. Accordingly, there is a need for improved DAC circuits.